Updates to the QDM generally occur annually and there are currently several versions of QDM available, although each for a different CMS reporting/performance period. See the eCQM Standards and Tools Versions table on the Electronic Clinical Quality Improvement (eCQI) Resource Center from the eCQI Tools & Key Resources page for the version by reporting year. Each measure documentation includes the QDM version number in the Clinical Quality Language file and the HTML human readable file.